Effects of kanamycin ototoxicity and hair cell regeneration on the DC endocochlear potential in adult chickens

Chen, Lin; Trautwein, Patricia G.; Miller, Karen E.; Salvi, Richard

doi:10.1016/0378-5955(95)00119-5

Cited by 13 publications

(3 citation statements)

References 41 publications

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“…6 shows a typical recording. EP values for the chicken ranged from 13.5 to 17.5 mV (median 14.3 mV), confirming previous measurements 7 25 . Values for the barn owl ranged from 30.1 to 44.3 mV (median 33.8 mV).…”

Section: Resultssupporting

confidence: 89%

Molecular bases of K+ secretory cells in the inner ear: shared and distinct features between birds and mammals

Wilms

Köppl

Söffgen

et al. 2016

Sci Rep

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In the cochlea, mammals maintain a uniquely high endolymphatic potential (EP), which is not observed in other vertebrate groups. However, a high [K+] is always present in the inner ear endolymph. Here, we show that Kir4.1, which is required in the mammalian stria vascularis to generate the highly positive EP, is absent in the functionally equivalent avian tegmentum vasculosum. In contrast, the molecular repertoire required for K+ secretion, specifically NKCC1, KCNQ1, KCNE1, BSND and CLC-K, is shared between the tegmentum vasculosum, the vestibular dark cells and the marginal cells of the stria vascularis. We further show that in barn owls, the tegmentum vasculosum is enlarged and a higher EP (~+34 mV) maintained, compared to other birds. Our data suggest that both the tegmentum vasculosum and the stratified stria vascularis evolved from an ancestral vestibular epithelium that already featured the major cell types of the auditory epithelia. Genetic recruitment of Kir4.1 specifically to strial melanocytes was then a crucial step in mammalian evolution enabling an increase in the cochlear EP. An increased EP may be related to high-frequency hearing, as this is a hallmark of barn owls among birds and mammals among amniotes.

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Section: Resultssupporting

confidence: 89%

Molecular bases of K+ secretory cells in the inner ear: shared and distinct features between birds and mammals

Wilms

Köppl

Söffgen

et al. 2016

Sci Rep

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show abstract

“…The EP was still elevated. This indicates that the functional impairments observed after kanamycin treatment are not due to a reduction in the driving force for the hair cell transduction current [Chen et al, 1995].…”

Section: Endocochlear Potentialmentioning

confidence: 81%

“…These effects may be due to reversible block of the transduction channels of the hair cells [Kroese et al, 1989] or blockage of basolateral ion channels [Dulon et al, 1989] by the aminoglycosides or sublethal interference with cell metabolism [Hashino and Shero, 1995;Hashino et al, 1997]. As the EP is not reduced after aminoglycoside trauma, it cannot be responsible for the global functional losses observed outside the area of total hair cell loss [Chen et al, 1995].…”

Section: Hair Cell Regeneration and Functional Recovery After Aminoglmentioning

confidence: 99%

Functional Recovery in the Avian Ear after Hair Cell Regeneration

Smolders

1999

Audiol Neurotol

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Trauma to the inner ear in birds, due to acoustic overstimulation or ototoxic aminoglycosides, can lead to hair cell loss which is followed by regeneration of new hair cells. These processes are paralleled by hearing loss followed by significant functional recovery. After acoustic trauma, functional recovery is rapid and nearly complete. The early and major part of functional recovery after sound trauma occurs before regenerated hair cells become functional. Even very intense sound trauma causes loss of only a proportion of the hair cell popu- lation, mainly so-called short hair cells residing on the abneural mobile part of the avian basilar membrane. Uncoupling of the tectorial membrane from the hair cells during sound overexposure may serve as a protection mechanism. The rapid functional recovery after sound trauma appears not to be associated with regeneration of the lost hair cells, but with repair processes involving the surviving hair cells. Small residual functional deficits after recovery are most likely associated with the missing upper fibrous layer of the tectorial membrane which fails to regenerate after sound trauma. After aminoglycoside trauma, functional recovery is slower and parallels the structural regeneration more closely. Aminoglycosides cause damage to both types of hair cells, starting at the basal (high frequency) part of the basilar papilla. However, functional hearing loss and recovery also occur at lower frequencies, associated with areas of the papilla where hair cells survive. Functional recovery in these low frequency areas is complete, whereas functional recovery in high frequency areas with complete hair cell loss is incomplete, despite regeneration of the hair cells. Permanent residual functional deficits remain. This indicates that in low frequency regions functional recovery after aminoglycosides involves repair of nonlethal injury to hair cells and/or hair cell-neural synapses. In the high frequency regions functional recovery involves regenerated hair cells. The permanent functional deficits after the regeneration process in these areas are most likely associated with functional deficits in the regenerated hair cells or shortcomings in the synaptic reconnections of nerve fibers with the regenerated hair cells. In conclusion, the avian inner ear appears to be much more resistant to trauma than the mammalian ear and possesses a considerable capacity for functional recovery based on repair processes along with its capacity to regenerate hair cells. The functional recovery in areas with regenerated hair cells is considerable but incomplete.

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Overview: Regeneration and Repair

Salvi¹

Hair Cell Regeneration, Repair, and Protection

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Effects of kanamycin ototoxicity and hair cell regeneration on the DC endocochlear potential in adult chickens

Cited by 13 publications

References 41 publications

Molecular bases of K+ secretory cells in the inner ear: shared and distinct features between birds and mammals

Molecular bases of K+ secretory cells in the inner ear: shared and distinct features between birds and mammals

Functional Recovery in the Avian Ear after Hair Cell Regeneration

Overview: Regeneration and Repair

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